Harvard University: Finding Hidden Heart Problems Faster

Heart attacks, the leading cause of death worldwide, are caused when plaque, that has built up on artery walls, dislodges and blocks the flow of blood to the heart.

Challenge

Up to 80% of heart attacks are caused by plaque that is not detectable by conventional medical imaging. Even viewing the 20% that is detectable requires invasive endoscopic procedures, which involve running several feet of tubing into the patient in an effort to take pictures of arterial plaque.

This level of uncertainty with regard to the exact location of potentially deadly plaque poses a significant challenge for cardiologists. Historically, it has been a guessing game for heart specialists to determine if and where to place arterial stents in patients with blockages. Knowing the location of the plaque could greatly improve patient care and save lives.

Solution

A team of researchers, including doctors at Harvard Medical School and Brigham & Women’s Hospital in Boston, Massachusetts, have discovered a non-invasive way to find dangerous plaque in a patient’s arteries. Tapping into the computational power of GPUs, they can create a highly individualized model of blood flow within a patient in a study called hemodynamics.

The buildup of plaque is highly correlated to the shape - or geometry - of a patient’s arterial structure. Bends in an artery tend to be areas where dangerous plaque is especially concentrated. Using imaging devices like a CT scan, scientists are able to create a model of a patient’s circulatory system. From there, an advanced fluid dynamics simulation of the blood flow through the patient’s arteries can be conducted on a computer to identify areas of reduced endothelial sheer stress on the arterial wall.

A complex simulation like this one requires billions of fluid elements to be modeled as they pass through an artery system. An area of reduced sheer stress indicates that plaque has formed on the interior artery walls, preventing the bloodstream from making contact with the inner wall. The overall output of the simulation provides doctors with an atherosclerotic risk map. The map provides cardiologists with the location of hidden plaque and can serve as an indicator as to where stents may eventually need to be placed - and all of this knowledge is gained without invasive imaging techniques or exploratory surgery.

Impact

GPUs provide 20x more computational power and an order of magnitude more performance per dollar to the application of image reconstruction and blood flow simulation, finally making such advanced simulation techniques practical at the clinical level.

Without GPUs, the amount of computing equipment - in terms of size and expense - would render a hemodynamics approach unusable. Because it can detect dangerous arterial plaque earlier than any other method, it is expected that this breakthrough could save numerous lives when it is approved for deployment in hospitals and research centers.

320 detector-row CT has enabled single heart beat coronary imaging so that the entire coronary contrast opacification can be evaluated at a single time point. The full 3D course of the arteries, in turn, allows researchers to simulate the blood flowing through it by using computational fluid flow simulations, and subsequently compute the endothelial shear stress.